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Old 01-03-2003, 01:25 PM   #1
Slalom RS
Scooby Specialist
Member#: 25577
Join Date: Oct 2002
Chapter/Region: NESIC
Location: Hooksett, NH, USA
2004 TS Wagon

Default Fuel Mileage has dropped since my K&N - normal?

About a month ago, I put in a K&N panel in my 00 RS. I commute a lot, and I keep a detailed log with every mod/tank of gas. I've gone from 24-26mpg to 21-23 since putting in the K&N. Is this normal? The last two tanks have been the worst, low 21.1xx mpg.

Also, this may or may not be related, but last week I was kicking out the snow that was packed into the back of the wheelwells after that Christmas storm up here in NH. When I got around to the passenger rear, I kicked it off and noticed that two wires were hanging down. On the way home, I got a CEL. I posted about this in the NESIC forum, and was told that it was the connectors that goes on the evap canister. I got under the car, noticed two holes, plugged the wires back in, and reset the ECU, which cleared the CEL. The two tanks after this occurance have been my worst...can resetting the ECU mess with your gas mileage? Thanks for the help...

My car just cleared 36k miles (and my warranty) two weeks ago...
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Old 01-03-2003, 01:58 PM   #2
Scooby Newbie
Member#: 9677
Join Date: Aug 2001
Location: Peoria, IL
2002 2.5 RS
Aspen White


I don't have an exact answer, but I am pretty sure your K&N did not cause your drop in gas mileage. My gas mileage always goes down this time of year. I'm sure that there are many reasons. Probably the biggest reason for me is more idling in the morning letting the windows defrost, the gas does not seem to be the same quality this time of year either. Also after resetting the ECU could have something to do with it. I think your good mileage will return.
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Old 01-03-2003, 02:05 PM   #3
Wheeler Bement
Scooby Specialist
Member#: 15652
Join Date: Feb 2002
Chapter/Region: TXIC
Location: sugar land, katy
2002 2.5L WRX Wag.
160K club


i have been told that reseting the ECU will make your gas mileage go down, i have noticed that too. also, check your tire pressure. i just did a trip to ohio from houston. the first tank i got 23 miles to the gallon, my tire pressure was 28-30. so i bumped the pressure up to 36-37 and got 27-29 miles to the gallon. but i don't think it would be a good idea to run high pressure on ice and snow, so this probably won't help. but in the spring time, maybe it will
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Old 01-03-2003, 04:50 PM   #4
Scooby Specialist
Member#: 20620
Join Date: Jun 2002
Chapter/Region: South East
Location: Canton, GA
2006 Outback 2.5 i
Willow Green Opal

Lightbulb FYI...

Slalom RS:

When I lived in NH, Hampstead, my gas mileage dropped dramatically during the winter. I believe your problem is related to winter gas!!! Have you tried switching gas brands??? I noticed my Subie ran better on Getty vs. other brands.

Good luck,
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